dyalisis Flashcards
what does diffusion allow in dialysis?
this allows removal of toxins which build up with ESKD:
- urea and creatinine
- potassium
- sodium
allows the infusion of bicarbonate
what does flow rate need to be for dialysis and how may it be achieved?
300- 350 mls/min
Vascular access using:
- arteriovenous fistula (AVF)
- arteriovenous graft (AVG)
- tunnelled central venous cetheter (TCVC)
- temporary venous catheter (vascath)
what does flow rate need to be for dialysis and how may it be achieved?
300- 350 mls/min
Vascular access using:
- arteriovenous fistula (AVF)
- arteriovenous graft (AVG)
- tunnelled central venous cetheter (TCVC)
- temporary venous catheter (vascath)
what is ultrafiltration in dialysis?
-the movement of water and all solutes dissolved in it, known as convection solute drag across a semi permeable membrane in response to a pressure gradient is known as ‘ultrafiltration’ in dialysis
what does adsorption affect?
- plasma proteins and any solutes that might be bound to them
- plasma proteins (especially those of low molecular weight) stick to the membrane surface and are removed by membrane binding
- high flux membranes adsorb protein bound solutes better than low flux membranes
what is the nature of haemodiafiltration?
-it is increasingly convective in nature
what is dialysis?
- a method for performing the filtration tasks of the kidneys artificially in patients with end stage renal failure or complications of renal failure
- it involves removing excess fluid, solutes and waste products
what are indications for acute dialysis?
AEIOU
- Acidosis (severe and not responding to treatment)
- Electrolyte abnormalities (severe + unresponsive hyperkalaemia)
- Intoxication (overdose of certain medications)
- Oedema (severe and unresponsive pulmonary oedema)
- Uraemia (symptoms such as seizures or reduced consciousness)
what are indications for long term dialysis?
- end stage renal failure (CKD stage 5)
- any of the acute indications continuing long term
what are the options of maintenance dialysis?
- continuous ambulatory peritoneal dialysis
- automated peritoneal dialysis
- haemodialysis
what is used as the filtration membrane in peritoneal dialysis?
-the peritoneal membrane
how does peritoneal dialysis work?
- it uses the peritoneal membrane as the filtration membrane
- a special dialysis solution containing dextrose is added to the peritoneal cavity
- ultrafiltration occurs from the blood, across the peritoneal membrane and in to the dialysis solution
- the dialysis solution is then replaced, taking away the waste products that have filtered out of the blood into the solution
what catheter is used in peritoneal dialysis?
Tenckhoff catheter
what are the different types of peritoneal dialysis?
- continuous ambulatory peritoneal dialysis
- automated dialysis
what’s the difference between continuous and automated dialysis?
continuous- the solution is in the peritoneum at all times, there are various regimes for changing the solution
automates- involves peritoneal dialysis occurring overnight. A machine continuously replaces dialysis fluid in abdomen overnight to optimise ultrafiltration
what are some complications of peritoneal dialysis?
- bacterial pericarditis
- peritoneal sclerosis
- ultrafiltration failure
- weight gain
- psychosocial effects
how long and how often is haemodyalisis?
- usually 4 hours long
- 3 sessions a week
what are the options for haemodyalisis?
- tunnel cuffed catheter
- anterior venous fistula
where is a tunnels cuffed catheter inserted?
-into the subclavian or jugular vein with a tip that sits in the superior vena cava or right atrium
what is the Dacron cuff?
- a ring that surrounds the catheter in the tunnelled cuffed catheter
- it promotes healing and adhesion of tissue to the cuff making the catheter more permanent and providing a barrier to bacterial infection
what are the main complications within the tunnelled cuffed catheter?
-infection and blood clots within the catheter
what is an A-V fistula?
- an artificial connection between an artery to a vein
- it bypasses the capillary system and allows blood to flow under high pressure from the artery directly into the vein
- this provides a permanent, large, easy access blood vessel with high pressure arterial blood flow
what is required to create an A-V fistula?
-surgical operation and a 4 week to 4 month maturation period without use
where is the A-V fistula normally formed between?
Radio- cephalic
Brachio- cephalic
Brachio- basilic (less common and more complex)
what should be done to examine A-V fistula?
- skin integrity
- aneurysms
- palpable thrill
- stereotypical ‘machinery murmur’ on auscultation
what are A-V fistula complications?
- Aneurysm
- Infection
- Thrombosis
- Stenosis
- STEAL syndrome
- High output heart failure
